WhatsApp may pride itself on having "no ads, no games, no gimmicks," but you can still use the service to sell your product or business.

The little-known (at least in the U.S.) messaging service came to the forefront last week, after Facebook handed over $19 billion in cash, shares, and stock to acquire the Mountain View, California-based company. The purchase was highly criticized, as the app, which costs just 99 cents a year after one year of free use, is mostly used by people outside the U.S. and doesn't have much in the way of revenue. But with nearly half a billion monthly users, it's hard to argue that the social-networking giant didn't know what it was doing.

The question is, how do you use it to help your business?

In countries where SMS messaging (a.k.a. text messaging) is less accessible or more expensive, WhatsApp is widely popular. Users rely on it to get in touch with family and friends internationally, and it’s a way around sky-high cell-phone bills.

Small businesses and artisans in countries such as India have used the application to communicate directly with clients and finalize sales. The new relationship between Facebook and WhatsApp makes this option even more intuitive.

Maintaining a social-media presence is crucial to building your brand--that’s a given. And while Facebook already allows you to keep in close contact with potential customers, as well as fans, WhatsApp takes it to the next level.

By enabling messaging functionality between businesses and prospective customers, that communication can be even closer and as immediate as a text message. In other countries, some businesses have put their WhatsApp numbers on advertisements and websites, letting the public know they can be reached using the application. Posting WhatsApp contact information in a Facebook status is also a common practice among individuals and retailers.

Specialized businesses, especially those who offer custom-made products to clients, have been adopting WhatsApp in India, according to Economic Times.

But should your business dial in? While the app may not be mainstream in the U.S., WhatsApp does offer a real-time way to connect with a massive global market. It costs practically nothing and doesn’t require the upkeep of other social networks that require active content production. It’s simply another avenue by which customers can reach you--and all you need is a phone number. Plus, texting is obviously popular among young Americans, so it's possible that the service could gain prominence at home, too.

Some might be unsettled by the prospect of fielding customer questions’ with their thumbs, but WhatsApp has also announced plans to add voice-call functionality in the second quarter, which will make it competitive with services such as Skype, as well as wireless networks.

WhatsApp is hardly the death knell for other means of communication. Responding to a deluge of queries using the application might not be the most ideal or sustainable way to conduct business. Never mind the social, as opposed to professional, connotation the WhatsApp name carries (although that could change).

And if you’re into SMS marketing, you should know that mass-messages are capped off at 50 recipients, though some entrepreneurs have found ways around it using third-party services (at a price).

Bottom line? WhatsApp is probably not a be-all, end-all solution to social-media marketing, but it’s only a dollar a year. You never know how many new customers you’ll connect with.